Rail cap



FIG. 1 is a perspective view;

FIG. 2 is a top view thereof;

FIG. 3 is a left side view thereof,;

FIG. 4 is an end view thereof, in which both ends appear the same;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a right side view thereof. 

The ornamental design for a rail cap, as shown and described. 